Changeset 6858 for FCSSimpleEndpoint

Timestamp:

11/30/15 16:13:27 (8 years ago)

Author:

Oliver Schonefeld

Message:

• check for parsing errors (oops)
• collect parsing errors and add appropriate FCS diagnostics

File:

• FCSSimpleEndpoint/trunk/src/main/java/eu/clarin/sru/server/fcs/FCSQueryParser.java (modified) (6 diffs)

FCSSimpleEndpoint/trunk/src/main/java/eu/clarin/sru/server/fcs/FCSQueryParser.java

@@ -1 +1 @@
 package eu.clarin.sru.server.fcs;
 
-import java.io.ByteArrayInputStream;
+import java.util.ArrayList;
 import java.util.Arrays;
 import java.util.Collections;
@@ -8 +8 @@
 
 import org.antlr.v4.runtime.ANTLRInputStream;
+import org.antlr.v4.runtime.BaseErrorListener;
 import org.antlr.v4.runtime.CommonTokenStream;
+import org.antlr.v4.runtime.RecognitionException;
+import org.antlr.v4.runtime.Recognizer;
 import org.antlr.v4.runtime.tree.ParseTree;
 import eu.clarin.sru.fcs.qlparser.FCSLexer;
@@ -57 +60 @@
     public SRUQuery<ParseTree> parseQuery(SRUVersion version,
             Map<String, String> parameters, SRUDiagnosticList diagnostics) {
+        FCSQuery result = null;
 
         final String rawQuery = parameters.get(PARAM_QUERY);
@@ -65 +69 @@
         }
 
+        ParseErrorListener errorListener = new ParseErrorListener();
         try {
-            ANTLRInputStream input = new ANTLRInputStream(
-                    new ByteArrayInputStream(
-                            rawQuery.getBytes("UTF-8")));
+            ANTLRInputStream input = new ANTLRInputStream(rawQuery);
             FCSLexer lexer = new FCSLexer(input);
             CommonTokenStream tokens = new CommonTokenStream(lexer);
             FCSParser parser = new FCSParser(tokens);
-            return new FCSQuery(rawQuery, parser, parser.query());
+            /*
+             * clear (possible) default error listeners and set our own!
+             */
+            lexer.removeErrorListeners();
+            lexer.addErrorListener(errorListener);
+            parser.removeErrorListeners();
+            parser.addErrorListener(errorListener);
+
+            /*
+             * other Lexer/Parser configuration ...
+             */
+            parser.setTrimParseTree(true);
+
+            /*
+             * commence parsing ...
+             */
+            ParseTree tree = parser.query();
+
+            if (!errorListener.hasErrors() &&
+                    (parser.getNumberOfSyntaxErrors() == 0)) {
+                result = new FCSQuery(rawQuery, parser, tree);
+            } else {
+                if (errorListener.hasErrors()) {
+                    for (String error : errorListener.getErrors()) {
+                        diagnostics.addDiagnostic(
+                                Constants.FCS_DIAGNOSTIC_GENERAL_QUERY_SYNTAX_ERROR,
+                                null, error);
+                    }
+                } else {
+                    diagnostics.addDiagnostic(
+                            Constants.FCS_DIAGNOSTIC_GENERAL_QUERY_SYNTAX_ERROR,
+                            null, "Query could not be parsed.");
+                }
+            }
         } catch (Exception e) {
-            diagnostics.addDiagnostic(SRUConstants.SRU_QUERY_SYNTAX_ERROR,
-                    null, "error parsing query");
+            diagnostics.addDiagnostic(SRUConstants.SRU_GENERAL_SYSTEM_ERROR,
+                    null, "Unexpected error while parsing query.");
         }
-        return null;
+        return result;
     }
 
@@ -84 +120 @@
         private final FCSParser parser;
 
-        private FCSQuery(String rawQuery, FCSParser parser, ParseTree parsedQuery) {
+        private FCSQuery(String rawQuery,
+                FCSParser parser,
+                ParseTree parsedQuery) {
             super(rawQuery, parsedQuery);
             this.parser = parser;
@@ -107 +145 @@
     }
 
+
+    private static final class ParseErrorListener extends BaseErrorListener {
+        private List<String> errors = null;
+
+
+        @Override
+        public void syntaxError(Recognizer<?, ?> recognizer,
+                Object offendingSymbol, int line, int charPositionInLine,
+                String msg, RecognitionException e) {
+            if (errors == null) {
+                errors = new ArrayList<String>();
+            }
+            errors.add(msg);
+        }
+
+
+        public boolean hasErrors() {
+            return (errors != null) && !errors.isEmpty();
+        }
+
+
+        public List<String> getErrors() {
+            return errors;
+        }
+    }
+
 } // class FCSQueryParser